The present invention relates to vacuum cleaners, and more particularly to the control of current drawn by the vacuum cleaner when it is operated as a vacuum or as a blower, and to the control of air flow within the vacuum cleaner.
Many vacuum cleaners have the capability of use, not only as a vacuum to draw debris into a tank or receptacle, but also as a blower. Vacuum cleaners that can be used as a blower generally have a blower port onto which a flexible or rigid hose is attached. The hose is then directed at debris to move unwanted material.
Underwriter""s Laboratories(copyright) creates certain standards for current (which is readily transferrable into power) for vacuum cleaners and blowers. The maximum permissible current that can be drawn is different with respect to a device used as a vacuum and as compared to a device used as a blower. When used in a vacuum mode, a maximum of 12 amps of current may be drawn at mean watts. Mean watts is defined as electric power drawn by the vacuum when the inlet to the vacuum cleaner is open, plus power drawn when the inlet to the vacuum cleaner is closed divided by two. When used as a blower, the maximum current that may be drawn is 12 amps when the blower is in the open mode. In general, in order to comply with the standards, a larger motor, which draws more current and power, can be used in the vacuum mode than can be used in a blower mode. It is also desirable to use a larger motor in a vacuum mode because a larger motor will be able to draw more air, measured in cubic feet per minute (CFM), and create a higher lift or pressure, which increases the performance of the vacuum cleaner.
It may also be desirable to use more than one air impeller in a vacuum cleaner. Two impellers can be driven off a single motor or two or more motors can be used, each having its own impeller or impellers. Under such circumstances, there may be a need to change the air flow through the various impellers to optimize performance under different conditions.
In accordance with certain aspects of the present invention, a vacuum cleaner is provided comprising at least one electric motor and an impeller disposed in an impeller housing, the impeller driven by the at least one electric motor. A receptacle is provided having an inlet and an orifice in fluid communication with the impeller housing, wherein the impeller creates a low pressure area in the receptacle thereby drawing air into the inlet. An outlet is in air flow communication with the impeller housing, wherein air from the impeller is expelled through the outlet. A switch, associated with the outlet, is provided, wherein the switch has a first position in which a first current may be drawn by the at least one motor and a second position in which a second current, less than the first current, may be drawn by the at least one motor. A device which may be removably attached to the outlet is provided, wherein the device directs air.
In accordance with additional aspects of the present invention, a vacuum is provided comprising a first electric motor, driving a first impeller, and a second motor driving a second impeller. A receptacle is provided having an inlet and an orifice establishing air flow communication between the receptacle and the first and second impellers. An outlet is in air flow communication with the first impeller and the second impeller. A valve is provided, wherein the valve is capable of converting air flow from series to parallel between the first impeller and second impeller.
Other features and advantages are inherent in the disclosed apparatus or will become apparent to those of ordinary skill in the art from the following detailed description and its accompanying drawings.